1. Field of the Invention
This invention relates to an apparatus for maneuvering a ship, and more particularly, to a type thereof which realizes the control of the direction of the trailing flow of the propellers of a Z-type propelling means by a single maneuvering handle.
2. Description of the Prior Art
Hitherto, three to five kinds of handles or levers have been utilized for maneuvering ships having two sets of Z-type propelling means. These handles or levers require complicated handling accomplished only by a skilled helmsman.
Therefore, a demand has existed to provide a single handle for maneuvering at least two sets of Z-type propelling means to provide the ship advancing direction equal to the handle direction, and ship speed proportional to the inclination angle of the handle.
U.S. Pat. No. 3,976,023 (commonly assigned) discloses such apparatus which comprises a maneuvering handle adapted to be inclined at any angle about a predetermined point. The ahead-astern switching transmitting device is adapted to issue electric signals for switching "ahead" and "astern" movement of the ship in accordance with the travel distance of the handle in one of two components, the sum constituting the angle of inclination of said handle. Steering transmitting means are adapted to issue signals for steering the ship to the port or starboard side in accordance with the travel distance of the handle in another component direction.
However, this system has a drawbacks in terms of the ship speed and the travel distance of the handle. That is, proportional relationship between the inclination angle of the handle and the ship speed would not be obtainable in all regions of use.
Therefore, the system for providing the ship speed in proportion to handle inclination amount is required for easy maneuverability. Further, according to conventional apparatuses, complicated electric circuits are provided and therefore, skilled techniques and long time are required to provide or to repair the same. Furthermore, the electric circuit limits the handle operation and therefore, mechanical means which functions instead of the one electric circuit is required to reduce or minimize the complicated electric circuit.
Referring to FIG. 7 of the prior art U.S. Pat. No. 3,976,023 it can be seen that at the positions to the extreme left and right on the neutral X axis the handle would be inclined to the extreme left or right positions but the speed is not correspondingly the greatest at those positions. For example, in the extreme leftward inclination maximum speed to port would be achieved in the upper right hand corner of that figure with both the propellors directed to the starboard side. The same would be true for speed to starboard. Hence, in this prior art system an area of settings exists where there is no corresponding relationship between ship speed and inclination angle of the handle. Then, areas exist in two triangular areas having an apex at the 0--0 neutral point in FIG. 7 and extending outward diagonally to the extreme corners of the chart, i.e. to the full port starboard, ahead and astern positions.